SPERMATOGENESIS IN THE CALIFORNIA OYSTER (OSTREA LURIDA)

Abstract

All individuals of this species in the locality investigated are hermaphroditic and protandric, the young gonad consisting of a distal layer of ovogonia with spermatogonia interspersed and filling much of the lumen. Each primary spermato-gonium divides 6-9 times to produce 64-512 primary spermatocytes, all held together in a gelatinous mass of secretion. This mass is then transformed into the so-called sperm-ball, containing from 250 to upwards of 2000 spermatozoa, by the 2 usual meiotic divisions. At the climax of the [male] phase many thousands of these sperm-balls are discharged into the mantle cavity and thence into the water. Others may be retained in the genital ducts, allowing self-fertilization in the ensuing [female] phase. The spermatozoa are liberated from sperm-balls by the solvent action of sea-water.